DAVIS, Calif., March 19 (UPI) -- Many of the changes in an adolescent brain making the transition to mature thinking and from childhood to adulthood occur during sleep, U.S. scientists say.

It involves pruning away excess neuronal connections necessary in youth to recover from injury and adapt to changing environments but which can impair the efficient problem-solving and logical thinking required later in life, they said.

"We've provided the first long-term, longitudinal description of developmental changes that take place in the brains of youngsters as they sleep," Irwin Feinberg, director of the University of California, Davis, Sleep Laboratory, said. "Our outcome confirms that the brain goes through a remarkable amount of reorganization during puberty that is necessary for complex thinking."

These changes can be detected by measuring the brain's electrical activity in the same children over the course of time, a university release said Tuesday.

The researchers said a rapid decline in that activity between the ages of 12 and 16-1/2 led them to conclude that the streamlining of brain activity -- or "neuronal pruning" -- required for adult cognition occurs together with the timing of reproductive maturity.

"Discovering that such extensive neuronal remodeling occurs within this 4-1/2 year time frame during late adolescence and the early teen years confirms our view that the sleep EEG indexes a crucial aspect of the timing of brain development," Feinberg said.

Star and black hole in dizzying dance

PARIS, March 19 (UPI) -- A star and a black hole are orbiting each other at the rate of once every 2.4 hours, smashing the previous record by nearly an hour, European astronomers say.

The black hole in this compact pairing discovered by the European Space Agency's XMM-Newton space telescope is at least three times more massive than the Sun while its red dwarf companion star has a mass only 20 percent that of the Sun, and the pair is separated by only around 600,00 miles, a release from ESA's Paris headquarters reported Tuesday.

The duo were discovered in September 2010 by NASA's Swift space telescope and were initially thought to be a gamma-ray burst, but more observations, including those by XMM-Newton, revealed that the radiation was coming from a black hole feeding off material ripped from a tiny companion.

Astronomers were able to determine the pair's orbital period was just 2.4 hours, setting a record for black hole X-ray binary systems. The previous recordholder has a period of 3.2 hours, they said.

The short orbital period results in the companion red dwarf star moving at a speed of 1.2 million miles per hour, making it the fastest moving star ever seen in an X-ray binary system, researchers said.

"The companion star revolves around the common center of mass at a dizzying rate, almost 20 times faster than Earth orbits the Sun," lead author Erik Kuulkers of ESA's European Space Astronomy Center in Spain said.

"You really wouldn't like to be on such a merry-go-round in this galactic fair!"

Origin of human cooperation may be ancient

WARWICK, England, March 19 (UPI) -- The origins of human teamwork may have ancient roots, European scientists say after discovering chimpanzees can also demonstrate the capability.

Researchers in Britain and Germany said in a series of trials, chimpanzees demonstrated the ability to coordinate their actions to achieve a common goal.

Pairs of chimpanzees given tools to retrieve grapes out of a box learned to solve the problem cooperatively, even swapping tools to pull the food out, they researchers said.

"Many animal species cooperate to achieve mutually beneficial goals like defending their territories or hunting prey," Alicia Melis of the University of Warwick in Britain said.

"However, the level of intentional coordination underlying these group actions is often unclear, and success could be due to independent but simultaneous actions towards the same goal.

"This study provides the first evidence that one of our closest primate relatives, the chimpanzees, not only intentionally coordinate actions with each other but that they even understand the necessity to help a partner performing her role in order to achieve the common goal," Melis said in a Warwick release Tuesday.

The researchers said they have been trying to find out if there are evolutionary roots to humans' ability to cooperate and coordinate actions.

"These are skills shared by both chimpanzees and humans, so such skills may have been present in their common ancestor before humans evolved their own complex forms of collaboration," Melis said.

The study by Warwick researchers and colleagues from the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, has been reported in the journal Biology Letters.

WASHINGTON, March 19 (UPI) -- British primatologist Jane Goodall has apologized for a book she co-authored using passages borrowed without attribution from a variety of websites.

"Seeds of Hope: Wisdom and Wonder From the World of Plants," co-authored with Gail Hudson, tells how botanists at the Kew Royal Botanical Gardens in London have successfully germinated 200-year-old seeds preserved in the Millennium Seed Bank.

The book includes borrowings ranging from phrases to an entire paragraph from websites such as Wikipedia and others, The Washington Post reported Tuesday.

"This was a long and well researched book," Goodall said in an email, "and I am distressed to discover that some of the excellent and valuable sources were not properly cited, and I want to express my sincere apologies."

Some of the borrowed material focused on astrology, tobacco, beer, nature and organic tea, the Post said.

"I hope it is obvious that my only objective was to learn as much as I could so that I could provide straightforward factual information distilled from a wide range of reliable sources," Goodall said in her email.

Co-author Hudson, described as a freelance writer, former spirituality editor for Amazon and longtime devotee of organic foods and holistic living, said she had no comment.

With the book set for release next month, Goodall said she would correct future editions.

In an email to the Post, the book's publisher, Grand Central, said it was surprised to "hear of the assertions."

"We have not formulated a detailed plan beyond crediting the sources in subsequent releases," it said.

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